The tree house is a great experience, and a little adventure very close to the heart of Bangkok. I had my own motorcycle, so the location wasn't an issue for me, but it's certainly not walking distance to Sukhumvit Rd. However, within walking distance just down the road there is a Family Mart and an amazing cafe - highly recommended!
The place itself is amazing. Loved all the animals and the slight thrill when the ducks chase you :-)
The tree house itself is very small. Somehow, despite having seen the photos and reviews, I still expected it to be bigger.
The biggest drawbacks are probably that the bathroom is separate downstairs and especially at night it's very uncomfortable... Secondly, the mattress is horrible. Very thin and very hard. I stayed 2 nights, and it's the absolute maximum I could bear - unfortunately. Lastly, please add some curtains/closures to the windows. I was here in the weekend and would have loved to sleep longer, but the bright sunlight didn't quite allow me to.
Despite these issues, as I wrote, it's a great experience and certainly worthwhile to see for a night at that price.
Communication with the owner was lightning fast and very friendly. Thank you very much!